A device of this kind is described in European published application No. 0 158 630. It consists of one or more identical modules each comprising a shielded loading and/or storage station for radiation sources, which may not be identical, and a push rod, and offers the possibility of separating the conveying device from a hollow needle in the radiation position by operating a coupling between the radiation source and the push rod that is releasable in the radiation position. The radiation source can be introduced into the hollow needle by the push rod under remote control, and is released and deposited therein. During the treatment the hollow needle can be separated from the push rod so as to give the patient a large measure of freedom of movement. At the end of the treatment the conveying device is again coupled with the hollow needle, so that after engagement of the coupling the individual radiation sources can again be withdrawn individually into the loading and/or storage station.
This known device has the disadvantage that a module with a conveying device is required for each radiation source. A further and more serious disadvantage is that in order to leave a radiation source in an applicator the coupling has to be released within the applicator. However, since the space available in hollow radiation needles for interstitial use is very limited, it is difficult to arrange a reliable release mechanism for the coupling in the radiation needle.